Why is Liao not included in the history of China?

Although there was a sinicization movement in Liao country, it was far from the level of Song Dynasty, and it was essentially equivalent to the successor of Tang Dynasty. Although the Song Dynasty was not a unified dynasty compared with the Jin and Liao Dynasties, it was much stronger than other regimes at that time in culture, science and commerce except military strength.

After the establishment of Liao country, it did not encounter too many strong enemies. At the end of the Tang Dynasty, the Central Plains was in chaos, and there was no energy to manage the rise and fall of grasslands. Yeluboji seized the historical opportunity, unified the Eight Departments of Qidan to build a city on the grassland, and set up Baiguan as the capital in Huanglinfu (southeast of Zuo Qi, Bahrain, Chifeng City), thus establishing the title of Qidan.

In 926 A.D., he marched eastward to the Bohai Sea and westward to the grassland tribes, reaching Central Asia, with an area twice that of the Northern Song Dynasty, and the Khitan was the best in the world, so that today's Eastern European and Central Asian countries still call China the Khitan.

The title of the Liao Dynasty:

The title of the Liao Dynasty is "Great Central Liao Qidan Country". Although the founding place of the Liao Dynasty was not the central place recognized by the Han people, the Liao Dynasty still claimed to be orthodox in China. When Emperor Taizong of Liao conferred the title of Emperor Shi Jingtang of Jin Dynasty, he once said, "You are just close friends, and you are really a branch. Therefore, if you are a child, just think of you as a father. "Shi Jingtang is talking about a country of father and son.

There are also "Hundred Kings Queli" and "Millennium Righteousness" in the book, which means that Shi Jingtang hopes to inherit and develop the tradition of "China" and become a descendant of China, while Shi Jingtang is the "closest relative" and "branch" of the Qidan people, meaning that "Qidan is China".

Refer to Baidu Encyclopedia-Liao Country for the above information.